SOUTH BERWICK, Maine — It took a year for David Mailhot to meet the woman whose life he saved.

Twelve months after doctors harvested two liters of bone marrow from four places along his Iliac crest, capping months of visits to the doctor's office, countless needles and too many blood samples, he prepared to sit down and say hello to a heretofore anonymous recipient. It was a peculiar kind of meeting, almost like a first date — with butterflies to match.

“I was nervous as hell,” Mailhot said weeks later. “As a matter of fact, I almost had my son stand in for me. I just wanted to make sure they liked me.”

After everything each of them went through to get to this point, anxiously waiting in front of computer screens thousands of miles apart, it was a good bet they would get along. After all, in a quite literal sense, each is now part of the other.

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Early in the summer of 2012, Mailhot, 48, of South Berwick, joined his siblings at the Mason's Lodge in Dover for a registry enrollment. Joining the Be The Match Registry of potential donors requires a quick DNA swab of cheek cells, taken from the mouth of the prospective donor. As long as one meets health guidelines and is between the ages of 18 and 60, the donor is then logged in a registry 11 million strong.

Of course, some of these good Samaritans are never called upon. The wait can be over in a few weeks, or could last years. Only one of every 500 people will eventually donate to a patient, according to the registry's website. The odds, then, were that Mailhot's well-meaning cheek swab would then be logged and subsequently passed over in the thousands of checks and reviews performed by medical professionals each year as they scour the planet for suitable, life-saving matches.

“It was funny because I didn't really expect to be called,” said Mailhot, a gregarious family man who races cars as a hobby.

Six months after the swab, Mailhot's phone rang. On the other line, a representative from the registry told him he came up as a match for a patient, and would he like to continue with the donation process?

“Oh, outstanding,” Mailhot replied. “Where do we go from here?”

Thus began the long, arduous process leading up to the donation of bone marrow. Unlike blood drives, when participants donate on site to a blood bank, marrow drives merely place someone on the proverbial list. That is only the first small, albeit very important, step, the first chapter in the donation opus, as Mailhot would soon discover.

“That just started a chain of going up to Dartmouth-Hitchcock and going through blood screening,” Mailhot said. “And a whole lot of needles. I hate needles.”

Barbara Nolan, the registry's Manager of Community Engagement for the Northeast district, explained some of the donor procedure. When doctors determine a patient needs a bone-marrow transplant, the registry is searched for potential matches. Sometimes there are multiple matches for a patient — if one isn't already found within the family. The transplant center will then determine which donor is the best option. At each stage, Mailhot had to sign consent forms, to ensure he knew what would be required of him.

“There's a lot of juggling that goes on,” Nolan said.

According to Nolan, Mailhot would have undergone an extensive physical, with doctors meticulously reviewing the health of the donor to ensure the procedure would not jeopardize his health. Doctors checked Mailhot's heart, back, spine and more in order to clear him for the more invasive of the two procedures. Donors will either have the marrow harvested from their hipbone — a surgical procedure — or through apheresis, a process similar to platelet donation. Before arriving at the donation center in Dartmouth, Mailhot went through about 20 to 30 hours of appointments over the course of four to six weeks.

“It's not like we're going to call you on Wednesday and you're going to donate Friday,” Nolan said. “It's a pretty substantial commitment.”

That's to say nothing of the patient, who must undergo her own series of appointments and checkups. Bone marrow transplants are often given to patients with leukemia, sickle cell disease, aplastic anemia or genetic disorders.

“Anything that is a disease related to blood cancers,” Nolan said.

Because the demands of receiving a bone-marrow transplant are often exhaustive, not to mention expensive, Nolan said doctors usually turn to transplant only after all other avenues of treatment have been explored. Seven out of every 10 patients are unable to find a match within their family, requiring use of the registry. That process will take some time.

Once a match is found, the patient undergoes a series of tests to make sure she will be able to receive the transplant without too negative an impact on her health. The patient then goes through her own physical and doctors examine medical records for information on previous infections and other pertinent history. When the time arrives, the patient will head to the hospital for the transplant, which will follow in a few days. Before then, the patient will receive a central line through which medication and the new marrow cells arrive.

To prepare for the transplant, the patient will be put through rigorous chemotherapy and possibly radiation therapy, which destroy the diseased cells in the bloodstream and blood-forming cells in the bone marrow. This essentially clears space for the arrival of the new blood or marrow, incapacitating the immune system long enough to keep it from attacking the newcomers. It's a debilitating process, and starts the clock ticking.

It was now time for Mailhot to give a little bit of himself to a stranger.

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Mailhot, whose LinkedIn page profile describes him as a technical solutions manager at Motor Coach Industries, admits he grew more anxious as the day approached.

“When it came time, there was a lot of buildup to the actual donation itself,” Mailhot said. “The timing has to work out. It became very nervous for me, because if I couldn't get up there or something happened, now the patient that you're donating for is kind of in a really weird spot. If I can't donate, it's not good.”

Despite his anxieties, everything with the donation went very well. Mailhot was laid on his front. Four insertion points were made on either side of the hipbone.

“The bone has pockets of marrow in it, so there's a certain percentage that we remove that regenerates itself in the next couple of weeks,” Nolan said.

For Mailhot, the only complications he had were during recovery, lying alone that night in his hospital bed. After coming to following the 90-minute procedure, he was transferred to a recovery room, where he would be staying overnight. It was a new experience.

“I've raced motorcycles and done stupid kid stuff,” Mailhot said. “That was the first time in my whole life I'd ever spent the night in the hospital. Having people wait on me was definitely uncomfortable.”

Around midnight, with the nurses all away to attend to another patient, Mailhot noticed his automatic bed was no longer able to move. Uncomfortable and unwilling to ask for help — he didn't want to trouble anyone, after all — the only thing to do was to fix it himself.

“So I kind of disconnected myself and crawled under the bed,” Mailhot said, offhandedly. “I didn't realize it had set an alarm off.”

Short two liters of marrow (“I didn't know I had that much!”) and with four punctures in his back, Mailhot, ever the handyman, proudly fixed the bed, but didn't get away without some scolding from the concerned nurses.

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The Be The Match program keeps the donation process as anonymous as possible. The recipient isn't told the identity of the donor, and the donor will not be told the identity of the recipient for at least a year, and only if each consents. Mailhot's anxieties about his personal responsibility for the health of the recipient may give some insight as to why this may be. After all, no well-meaning person would want to feel an overbearing sense of responsibility for such an important, often life-saving procedure. So for months, Mailhot lived in ignorance as to just where his two liters of goodwill went.

Following the harvest, a courier transports the marrow from the donation site to where the recipient stays, awaiting transplant. According to Nolan, those couriers are working against a clock. The donated marrow must be transplanted within 72 hours. With donors worldwide, this occasionally requires very fast travel.

The recipient then receives the donated marrow or cells through a transfusion-like process.

“The theory is then that the bone marrow or the stem cells will find its way to the large bones and start regenerating healthy blood cells,” Nolan said.

Those reproduced blood cells are essentially the blood of the donor, meaning that a recipient's blood type may change after the procedure. In a very real way, Mailhot's blood is now running through his recipient's veins.

“What's amazing, it makes me feel so good, there are people out there that are so selfless,” Nolan said. “It's bigger than him and it's bigger than the recipient. Once you've done something like this, it's just one of those things that you now know you can rest easy. You're part of someone's solution.”

Doctors supervise the patient for about three months to ensure the transplant was successful. The patient is then allowed to leave the hospital, but is required to undergo frequent checkups. After 12 months, Mailhot was permitted to speak to the recipient, a California woman of about 50. Mailhot sent a request asking if she would be willing to speak with Foster's for this story, but was unable to get a response at the time of writing.

“They asked me if I wanted to know anything about the recipient,” Mailhot said. “What happens if it doesn't work? That was just my hang-up. Would you want to not hear anything and have the center say, unfortunately your recipient didn't make it? You don't want to carry that around. You don't want to feel responsible.”

Despite these fears, at the encouragement of his family, Mailhot eventually agreed to speak with the recipient over Skype. There were other things to think about in the minutes before the call.

“What do I wear?” Mailhot said. “Should I get my hair cut?”

It was only during the call, after shaking off those butterflies, that Mailhot said he fully understood the impact of his donation.

“I never really realized until we had this meeting just what happened,” Mailhot said. “To me, I got the call and I did what I needed to do, and you'd hope that's what everybody would do. They told her if this doesn't happen, that was it. I was the only option. It was so great to see them and hear this story.”

The recipient thanked Mailhot through tears, introducing him to the entire family, including her husband and children, even the dog.

“They were all so appreciative,” Mailhot said. “They would have lost their mother. I didn't realize the level of impact this would have on their family and really what it entailed. It really didn't strike me until this conversation with her.”

Mailhot said there has been some discussion of meeting in person, maybe sometime this summer. He said her family, which is very close-knit, was anxious to find out as much as they could about the man with, as his mother put it, a “big personality.” Now, this race-car-driving, do-it-yourself, life-saving, humble and humorous man is part of another woman's life forever.

“My DNA is now going to be in another body,” Mailhot said. “I joked about that. I said, 'You're probably going to drive a lot faster now.'”